Problem: $\overline{AC}$ is $3$ units long $\overline{BC}$ is $6$ units long $\overline{AB}$ is $3\sqrt{5}$ units long What is $\cos(\angle BAC)$ ? $A$ $C$ $B$ $3$ $6$ $3\sqrt{5}$
Answer: SOH CAH TOA os = djacent over ypotenuse adjacent $= \overline{AC} = 3$ hypotenuse $= \overline{AB} = 3\sqrt{5}$ $\cos(\angle BAC )=\frac{3}{3\sqrt{5}}$ $=\dfrac{ \sqrt{5}}{5}$